Went home for lunch. Took out the original memory simm and replaced it with the one purchased yesterday. In either slot, the PC doesn't boot and I get the series of long beeps. Put in the original with the new one, tried booting - got beeps. Switched them in the slots - same old beeping. Pulled out the new one, left in the original - boots up OK. Put it into the other slot - ditto; boots up fine.

I'd say the memory was bad. Now I have to go argue with Akmed that he sold me a bad simm and to replace it, no matter that it says on the receipt "All Sales Final".